Speed, 38 joined Sheffield United last January in a £250,000 deal from Premiership outfit Bolton Wanderers, making his debut in the 0-0 draw with Wolverhampton Wanderers at Molineux on 1st January.
The midfielder quitted international football with Wales have earned 86 caps and scored eight goals whist he currently has featured in 660 Football League fixtures and scored 100 goals.
He joined the Blades with a view to taking up a Player-Coaching role at Bramall lane and has hinted that next seasons Championship campaign may well be his last.
"It could be my last season, but then again it may not be, we will have to wait and see," said Speed.